Conventionally, in imaging using an X-ray CT (Computed Tomography) apparatus, a scan protocol for collecting data is set depending on an examination site and examination contents. As the scan protocol, a scan protocol candidate suitable for the examination site and examination contents is selected from a plurality of preset scan protocol candidates, and a preset condition is set by being adjusted appropriately. The respective scan protocol candidates are divided depending on the age, adult/child, male/female, weight, body type such as height, and examination object. Various conditions, such as an imaging range of a positioning image (a scanogram image) for setting an imaging range, an imaging angle of the scanogram image, a tube voltage and a tube current at the time of taking the positioning image, a scan method, a scan position, and a scan range of main imaging (scanning) for collecting data to be used for diagnosis, a tube voltage and a tube current at the time of performing the scan, and the position and range in image reconstruction, are set in advance.
There has been known a method for recognizing a site included in a scanogram image and using information thereof for setting the various conditions described above. In such a method, for example, the scanogram images are collected three-dimensionally by helical scan, a site is automatically recognized based on geometric features of the collected scanogram images, and an imaging condition suitable for the recognized site is set.